A fast shutdown system and method for a linear induction accelerator

Abstract

The application discloses a quick closing system and method applied to a linear induction accelerator, and belongs to the technical field of the high-current linear induction accelerator. The quick closing valve assembly is arranged in the drift pipe of the beam transport and focusing system downstream of the accelerator. The pulse trigger signal is used to remotely load the control system, and the control system sends the instruction to control the closing action of the quick closing valve assembly, so that the quick closing valve assembly is opened and closed after the electron beam passes through the quick closing valve assembly. Before the backflow particles reach the position of the quick closing valve assembly, the complete closing of the valve assembly is completed, so that the backflow metal particles in the reverse motion can be blocked, and the deposition or collision of the backflow metal particles in the internal part of the accelerating component is avoided, so that the damage and influence on the performance of the accelerator are avoided.

Description

Technical Field

[0001] This invention belongs to the technical field of high-current linear induction accelerators, specifically relating to a rapid shutdown system and method for linear induction accelerators. Background Technology

[0002] A linear induction accelerator, consisting of an injector, accelerating components, a pulsed power system, a beam transport and focusing system, a bremsstrahlung conversion target system, an auxiliary system, and a synchronous control triggering and monitoring system, can generate high-current pulsed electron beams. Each pulsed electron beam has a current intensity of several kA, an energy of tens of MeV, a pulse width of tens of ns (FWHM), and the number of pulses can be a single pulse or a multi-pulse with a frequency of MHz.

[0003] The pulsed electron beam generated by the injector electron beam source undergoes multi-stage acceleration by the accelerating components, increasing the electron beam energy to tens of MeV and achieving a speed close to the speed of light. The pulsed power system provides pulsed power to the injector and the main body of the accelerating components. The beam transport and focusing system constrains the accelerated electron beam and ensures that the electron beam is transmitted and focused to the desired size, generally on the order of ~mm. In addition, auxiliary systems, synchronous control triggering and monitoring systems, and testing systems ensure the normal operation of all components of the linear induction accelerator.

[0004] A high-current pulsed electron beam generated by a linear induction accelerator is focused into a millimeter-sized beam spot and interacts with a bremsstrahlung conversion target to produce a large dose of X-rays. These pulsed X-rays are used to penetrate high-speed moving objects and form images on an image detector, thereby obtaining information about the internal dynamic processes of the object. This method is generally used in flash photography experiments and other radiation detection experiments.

[0005] When a high-current pulsed electron beam interacts with a bremsstrahlung target, the bremsstrahlung effect can generate a large dose of pulsed X-rays. Simultaneously, the interaction between electrons and the atoms of the bremsstrahlung target material causes a large amount of energy deposition on the target. This energy deposition causes a rapid temperature increase in the bremsstrahlung target material within a very short time, leading to rapid expansion and dispersion of the target material. This results in a reduction in the amount of bremsstrahlung target material and a decrease in its density. In the case of multi-pulse electron beams, after the first pulse, due to the loss of target material, there may be no usable bremsstrahlung target material for the subsequent second and third pulses. This would prevent the generation of continuous, multi-pulse, high-dose X-rays, failing to meet the requirements for multi-flash X-ray radiography. Furthermore, the ablation and melting of the bremsstrahlung target material, under the influence of shock waves and thermal shock waves, causes some ablation debris (in the form of particles) to move upstream of the accelerator. These moving target particles are called recirculated metal particles. The returning metal particles have a speed of ~km / s and will quickly move into the accelerator components upstream of the accelerator. After a large number of beam-target interactions, the metal particles deposited in the accelerator components will cause a decrease in the insulation performance of the accelerator components, which may lead to high voltage breakdown and affect the normal operation performance of the accelerator. Summary of the Invention

[0006] To address the problem of backflow particles in current high-current pulsed linear induction accelerators, caused by the expansion of the bremsstrahlung target material and particle scattering due to the interaction between the pulsed electron beam and the target, leading to decreased insulation performance and high-voltage breakdown in accelerator components, this invention provides a rapid shutdown system and method for linear induction accelerators. This invention completely blocks backflowing metal particles through the rapid shutdown function of the rapid shutdown system, preventing contamination upstream of the accelerator and ensuring stable accelerator performance.

[0007] This invention is achieved through the following technical solution:

[0008] A rapid shut-off system for a linear induction accelerator includes a rapid shut-off valve assembly, a control system, and an external pulse signal system;

[0009] The fast-closing valve assembly is installed in the beam drift pipe of the beam transport and focusing system of the linear induction accelerator;

[0010] The rapid-closing valve assembly is in the open state when the electron beam is propagating in the beam drift channel;

[0011] After the electron beam passes through the rapid-closing valve assembly, the rapid-closing valve assembly closes under the trigger signal of the external pulse signal system and the control system to block the backflow of metal particles generated in the linear induction accelerator.

[0012] This invention involves installing a fast-closing valve assembly within the drift channel of the beam transport and focusing system downstream of the accelerator. An external pulse trigger signal remotely loads the control system, which then issues commands to control the closing action of the fast-closing valve assembly. This ensures that the fast-closing valve assembly is open when the electron beam is propagating within the beam channel, and closes as soon as the electron beam passes through it. The valve assembly fully closes before the returning particles reach its position, thus blocking the backflow of metal particles. The remote pulse signal triggering of the fast-closing valve assembly enables its early closure, preventing backflow of metal particles from depositing or colliding inside the accelerator components and causing damage or impact on accelerator performance.

[0013] As a preferred embodiment, the quick-closing valve assembly of the present invention includes a control gate, a piston, a pneumatic transmission device, a cavity wall, and a monitoring column;

[0014] The cavity wall is a pipe structure with openings at both ends, and a control door is provided at one of the openings; the control door is a circular structure that can completely close the opening of the cavity wall.

[0015] The top of the control door is connected to the bottom of the pneumatic transmission device, and the top of the pneumatic transmission device is connected to a piston. The control door moves radially along the cavity wall under the drive of the piston and the pneumatic transmission device, thereby realizing the opening and closing of the control door.

[0016] The piston is located inside the piston chamber, and an external gas pipe seat is provided on the piston chamber. The external gas pipe seat is connected to a gas supply pipe for filling the piston chamber with gas.

[0017] The monitoring column is located on top of the quick-closing valve assembly and is connected to the piston for monitoring the movement of the piston and the control door.

[0018] In a preferred embodiment, a sealing groove is provided on the inner wall of the cavity tube wall near the control door to achieve a vacuum seal between the control door and the cavity tube wall.

[0019] In a preferred embodiment, the cavity wall of the fast-closing valve assembly of the present invention is connected to the beam pipe of the linear induction accelerator. The part of the fast-closing valve assembly other than the cavity wall is connected to the beam pipe through the cavity, and the vacuum degree inside the pipe remains consistent.

[0020] In a preferred embodiment, the closing diameter of the quick-closing valve assembly of the present invention is 100 mm.

[0021] In a preferred embodiment, when the quick-closing valve assembly of the present invention is in the fully open state, the monitoring column extends 25mm beyond the top of the quick-closing valve assembly.

[0022] In a preferred embodiment, the control system of the present invention includes a control panel;

[0023] The control panel has three status switches and two valve open / close indicator lights on the front.

[0024] The three status switches are the local key, the lock key, and the remote key;

[0025] The two valve opening / closing indicator lights are the valve open light and the valve closed light, respectively.

[0026] The back of the control panel is equipped with a valve connection pipe seat and an external trigger signal connection pipe seat;

[0027] The valve connection pipe seat is used to connect the control system to the quick-closing valve assembly, so as to transmit the pulse trigger signal output by the control system to the quick-closing valve assembly, thereby remotely controlling the opening and closing actions of the quick-closing valve assembly;

[0028] The external trigger signal connector is used to connect the external pulse signal system to the control system, so as to transmit the pulse signal output by the external pulse signal system to the control system.

[0029] As a preferred embodiment, the external pulse signal system of the present invention includes a synchronous triggering control and monitoring system for a linear induction accelerator and a signal source;

[0030] The synchronous triggering control and monitoring system is connected to the signal source;

[0031] The pulse signal emitted by the synchronous trigger control and monitoring system is transmitted to the signal source;

[0032] The signal source generates a pulse signal with varying amplitude and width, and loads it into the control system, which remotely controls the opening and closing actions of the rapid-closing valve assembly.

[0033] In a preferred embodiment, the closing speed of the fast closing system of the present invention is not less than 1 km / s, and the complete closing time is not greater than 9 ms.

[0034] Secondly, the present invention proposes a working method based on the above-mentioned fast shutdown system, including:

[0035] The linear induction accelerator is activated, and its injector generates a pulsed electron beam. After passing through the acceleration component system and the beam transport and focusing system, the electron beam moves toward the bremsstrahlung target at a speed close to the speed of light and a beam spot size on the order of millimeters, and interacts with the bremsstrahlung target.

[0036] When the electron beam propagates within the beam drift channel, the rapid-closing valve assembly is in the open state;

[0037] When the electron beam passes through the fast-closing valve assembly, the external pulse signal system generates a pulse signal and transmits it to the control system, changing the triggering method of the control system to control the valve action and triggering the closing action of the fast-closing valve assembly.

[0038] The present invention has the following advantages and beneficial effects:

[0039] This invention incorporates a fast-closing valve assembly in the beam transport and focusing system of a linear induction accelerator. An external pulse signal system outputs a pulse signal that is remotely applied to the control system. The control system generates a control command to control the fast-closing valve assembly to perform a rapid closing action after the electron beam passes through the fast valve assembly. This blocks the backflow of target material metal particles generated by beam-target interaction, protecting the accelerator components upstream of the accelerator from contamination by the backflow of metal particles.

[0040] The quick-closing valve assembly of the present invention includes a control gate that enables rapid closure. Under nitrogen pressure, the control gate is driven by a pneumatic transmission device to move at high speed, and the control gate and the valve cavity close rapidly, thereby realizing the closure of the quick-closing valve assembly.

[0041] Based on the layout of the accelerator beam drift channel, the present invention enables the rapid closing valve assembly to quickly close the control door under the drive of a trigger signal, and the closing time can reach the millisecond level. This can effectively block the ultrafast reflowing metal particles generated by the bremsstrahlung target material with a speed of up to ~km / s.

[0042] Compared to existing blocking devices, the fast-closing valve assembly provided by this invention is vacuum connected to the beam drift pipe, which does not affect the continuity of high-current pulsed electron beam transmission, beam quality, or X-ray quality. While ensuring the stability and safety of the high-flow pipe, it greatly improves experimental efficiency.

[0043] This invention can effectively reduce the damage and impact of recirculated metal particles on accelerator components, improve the service life of accelerator components, thereby reducing daily maintenance time and costs, and increase the number of daily operation experiments of the accelerator, thus improving the application efficiency of linear induction accelerators; the number of light emission experiments in daily operation can be increased to more than 150% of the original number. Attached Figure Description

[0044] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0045] Figure 1 This is a schematic diagram of the fast shutdown system structure according to an embodiment of the present invention.

[0046] Figure 2 This is a schematic diagram of the quick-closing valve assembly structure according to an embodiment of the present invention, wherein: (a) is the closed state and (b) is the open state.

[0047] Figure 3 This is a schematic diagram showing the connection between the fast-closing valve assembly and the accelerator beam pipeline in an embodiment of the present invention.

[0048] Figure 4 This is a waveform diagram of the voltage pulse trigger signal in an embodiment of the present invention.

[0049] Figure 5 This is a schematic diagram illustrating the measurement of the closing time of the fast-closing valve assembly according to an embodiment of the present invention.

[0050] The attached diagram shows the markings and corresponding component names:

[0051] 1-Control door, 2-External air pipe seat, 3-Piston, 4-Pneumatic transmission device, 5-Cavity wall, 6-Monitoring column, 7-Sealing groove. Detailed Implementation

[0052] In the following, the terms “comprising” or “may include” as used in various embodiments of the invention indicate the presence of an inventive function, operation, or element, and do not limit the addition of one or more functions, operations, or elements. Furthermore, as used in various embodiments of the invention, the terms “comprising,” “having,” and their cognates are intended only to indicate a specific feature, number, step, operation, element, component, or combination of the foregoing, and should not be construed as primarily excluding the presence of one or more other features, numbers, steps, operations, elements, components, or combinations of the foregoing, or adding one or more combinations of the foregoing.

[0053] In various embodiments of the invention, the expression "or" or "at least one of A and / or B" includes any combination or all combinations of the words listed simultaneously. For example, the expression "A or B" or "at least one of A and / or B" may include A, may include B, or may include both A and B.

[0054] The expressions used in the various embodiments of the present invention (such as "first," "second," etc.) may modify various constituent elements in the various embodiments, but do not limit the corresponding constituent elements. For example, the above expressions do not limit the order and / or importance of the elements. The above expressions are only used for the purpose of distinguishing one element from other elements. For example, a first user device and a second user device refer to different user devices, although both are user devices. For example, a first element may be referred to as a second element without departing from the scope of the various embodiments of the present invention, and similarly, a second element may also be referred to as a first element.

[0055] It should be noted that if a description is made of "connecting" one component to another, then the first component can be directly connected to the second component, and a third component can be "connected" between the first and second components. Conversely, when a component is "directly connected" to another component, it can be understood that there is no third component between the first and second components.

[0056] The terminology used in the various embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to limit the various embodiments of the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which the various embodiments of the invention pertain. The terms (such as those defined in a generally used dictionary) are to be interpreted as having the same meaning as in the context of the relevant technical field and are not to be interpreted as having an idealized or overly formal meaning, unless clearly defined in the various embodiments of the invention.

[0057] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0058] Example

[0059] In existing high-current pulsed linear induction accelerators, after numerous beam-target interaction experiments, a certain number and scale of recirculated metal particles deposit on the insulating support material of some accelerator components. This leads to high-voltage breakdown in some accelerator components, reducing their service life. Based on this, this embodiment provides a rapid shut-off system for linear induction accelerators. This invention installs a rapid shut-off valve assembly in the drift pipe of the beam transport and focusing system downstream of the accelerator. An external pulse trigger signal remotely loads the control system, which then issues commands to achieve high-speed movement of the control gate of the rapid shut-off valve assembly. When the electron beam propagates within the beam pipe, the control gate is open; when the electron beam passes through the control gate area, the control gate opens and closes. The control gate is completely closed before the recirculated particles reach the rapid shut-off valve position, thus blocking the recirculated metal particles and preventing their deposition or collision inside the accelerator components, which could damage or affect accelerator performance.

[0060] Specifically, such as Figure 1 As shown, the rapid shut-off system includes: a rapid shut-off valve assembly, a control system, and an external pulse signal system. The rapid shut-off valve assembly is electrically connected to the control system, and the control system is electrically connected to the external pulse signal system.

[0061] The quick-closing valve assembly includes a control valve 1, an external air pipe seat 2, a piston 3, a pneumatic transmission device 4, a cavity wall 5, a monitoring column 6, and a sealing groove 7, such as... Figure 2 As shown, the cavity tube wall 5 is a pipe structure with openings at both ends, and the control door 1 is a circular flat plate structure that can seal the openings of the cavity tube wall 5 (i.e., the diameter of the control door 1 is greater than or equal to the inner diameter of the opening of the cavity tube wall 5). Furthermore, the inner diameter of the cavity tube wall 5 matches the inner diameter of the accelerator beam pipe, allowing for a vacuum seal connection to the accelerator beam pipe. The top of the control door 1 is connected to the bottom of the pneumatic transmission device 4, and the top of the pneumatic transmission device 4 is connected to the piston 3. 。When the quick-closing valve assembly is in the open state, the control door 1 is in a horizontal position parallel to the axis of the cavity wall 5. When the trigger command (electric pulse signal) of the control system is transmitted to the quick-closing valve assembly, the control door 1 can rotate clockwise along the cavity wall 5 under the drive of the piston 3 and the pneumatic transmission device 4, so that the control door 1 is in complete contact with the sealing groove 7, thereby closing the control door 1. At this time, the quick-closing valve assembly is in the closed state. Conversely, the control door 1 can rotate counterclockwise along the cavity wall 5 under the reverse drive of the piston 3 and the pneumatic transmission device 4. When the control door 1 is completely parallel to the axis of the cavity wall 5, the control door 1 is opened, and the quick-closing valve assembly is in the open state. Piston 3 is located inside the piston chamber, and an external gas pipe seat 2 is installed on the piston chamber. The external gas pipe seat 2 is connected to a gas supply pipe for filling the piston chamber with nitrogen gas. Monitoring column 6 is located on top of the quick-closing valve assembly and is connected to piston 3. It is used to monitor the movement of piston 3 and control door 1. Monitoring column 6 can be moved up and down by piston 3. Sealing groove 7 is set on the inner wall of the cavity tube wall 5 at the opening of the control door 1, for achieving a vacuum seal between the control door 1 and the cavity tube wall 5. The quick-closing valve assembly is vertically installed between the accelerator beam drift pipes. The openings at both ends of the cavity tube wall 5 are sealed to the beam drift pipes at both ends by a bayonet seal. The other parts are connected to the beam drift pipes, and the vacuum level is kept consistent. Figure 3 The diagram shows the connection between the switching valve and the pipes at both ends in the beam transmission section of the accelerator.

[0062] The control system includes a control panel. The front of the control panel features three status switches (Local, Locked, and Remote) and two valve open / close indicator lights. The back of the control panel has a 19-pin valve connector and a 12-pin external trigger signal connector. The external trigger signal connector connects the external pulse signal system to the control system, remotely transmitting the pulse signals output by the external pulse signal system to the control system. The valve connector connects the control system to the fast-closing valve assembly, and through internal conversion by the control system, outputs different pulse voltage signals to the fast-closing valve assembly, thereby controlling the opening and closing actions of the fast-closing valve assembly.

[0063] The external pulse signal system includes a LIA (Linear Induction Accelerator Synchronous Trigger Control and Monitoring System) main control console and a signal source. The LIA main control console is connected to the signal source, and the pulse signal emitted by the LIA main control console is transmitted to the signal source, which controls the signal source to generate a pulse trigger signal with varying amplitude and pulse width. The pulse trigger signal output by the signal source is remotely loaded onto the control system, which enables remote control of the opening and closing actions of the valve assembly.

[0064] The working principle of the fast shutdown system proposed in this embodiment is as follows:

[0065] In the beam transport drift channel of the linear induction accelerator, at a certain distance from the bremsstrahlung target, a fast-closing valve assembly is connected to the beam transport channel via the cavity wall 5, maintaining a vacuum environment inside the valve assembly. The pulsed electron beam generated by the linear induction accelerator interacts with the bremsstrahlung target, producing target metal particles (i.e., backflow particles) moving upstream of the accelerator. A delayed synchronous trigger pulse signal from the LIA main control console in the external pulse signal system is transmitted to the signal source. The signal source generates and outputs a low-voltage pulse signal, which is remotely loaded into the control system, changing the triggering mode of the control valve action within the control system (the control system controls the fast-closing valve assembly to be in the open state when the electron beam passes through). When backflow particles are generated and move in reverse, the control system controls the fast-closing valve assembly to quickly close the control gate within milliseconds via the low-voltage pulse signal, blocking the backflow particles from moving upstream of the accelerator. This eliminates the decrease in the insulation capacity of the accelerator components and the occurrence of high-voltage breakdown caused by the accumulation of backflow particles within the accelerator.

[0066] This embodiment incorporates a fast-closing valve assembly installed within the drift channel of the beam transport and focusing system downstream of the accelerator. An external pulse trigger signal remotely loads the control system, which then issues commands to control the high-speed movement of the fast-closing valve assembly's gate. When the electron beam travels within the beam channel, the gate is open; as the beam passes through the gate's region, it automatically closes, completing the gate's full closure before the returning particles reach its position. This effectively blocks the backflowing metal particles. The remote pulse signal triggering of the fast-closing valve assembly enables early closure of the gate, preventing backflowing metal particles from depositing or colliding within the accelerator components and causing damage or impact on accelerator performance.

[0067] In practical applications, the closing time of the rapid shut-off system in this embodiment is related to its installation position in the accelerator beam drift channel, i.e., the distance between it and the bremsstrahlung target, and also to the diameter of the control gate. For the same distance from the target, the smaller the control gate diameter, the shorter the closing time, which can more effectively block high-speed backflowing metal particles.

[0068] In this embodiment, based on the distance between the bremsstrahlung target and the installation position of the quick-closing valve assembly, and the movement speed of the returning particles, the valve control gate closing time is required to be less than 15ms. The closing diameter of the control gate of the quick-closing valve assembly is 100mm (i.e., the inner diameter of the opening of the quick-closing valve assembly). The working process of the quick-closing system is as follows:

[0069] The linear induction accelerator is activated, and its injector generates a pulsed electron beam. After passing through the acceleration component system and the beam transport and focusing system, the electron beam moves toward the bremsstrahlung target at a speed close to the speed of light and a beam spot size on the order of millimeters, and interacts with the bremsstrahlung target.

[0070] When the electron beam propagates within the beam channel, the rapid-closing valve assembly is in normal working condition. Nitrogen gas at a pressure of (0.5~0.8) MPa is introduced through the external gas pipe socket. Initially, the rapid-closing valve assembly is in the open state (i.e., the control door is in the open state). The distance between the rapid-closing valve assembly and the bremsstrahlung target is 18m. The indicator rod of the monitoring column 6 is in the extended state, with an extension platform height of 25mm. The control door 1 is parallel to and close to the opening of the valve assembly cavity wall. The valve opening light on the control panel is turned on, and the opening light is lit. The status switch button is in the remote key position. At this time, the rapid-closing valve assembly is in the remotely controllable trigger state.

[0071] The synchronous control triggering and monitoring system (LIA main console) of the linear induction accelerator outputs a fast pulse signal (voltage amplitude 5V, pulse width 120ns) and transmits it to the signal source. After internal conversion by the signal source, a pulse signal with a pulse width of 10ms and a voltage amplitude of 5V is generated, such as... Figure 4 As shown, it is remotely transmitted to the control system;

[0072] The pulse signal triggering control system sends a closing command to the fast-closing valve assembly. The piston 3 of the fast-closing valve moves from top to bottom under the action of nitrogen pressure, pushing the pneumatic transmission device 4, thereby driving the control door 1 to start high-speed movement until it stops after completely closing with the sealing groove 7 of the cavity wall 5.

[0073] The monitoring column 6 moves rapidly downwards under the action of the piston, eventually reaching the same height as the platform, meaning that no part of the monitoring column 6 is exposed. At this point, the closing process of the rapid-closing valve assembly is complete. The closing time of the control door, from the start of the fast pulse trigger signal to the complete closure of the control door of the rapid-closing valve assembly, is approximately 8.8 ms (i.e., less than 9 ms). Figure 5 As shown, the accelerator beam pipe is blocked by a rapid-closing valve assembly, and the returning metal particles are completely blocked by the rapid-closing valve assembly.

[0074] Turn on the local status switch on the control panel of the control system. Turn on the valve opening light. The opening light will start flashing continuously until the valve closes and the light turns off. At this time, the opening process of the rapid valve closing assembly is completed, and the accelerator beam transmission pipeline is in a fully open state, ready for the next accelerator operation experiment.

[0075] Experimental tests have demonstrated that the rapid shutdown system proposed in this embodiment, applied to a linear induction accelerator, effectively blocks the backflow of metal particles generated by the bremsstrahlung target under the influence of a pulsed high-current electron beam. The installation of the rapid shutdown valve assembly does not affect the normal movement of the electron beam during the beam drift phase, significantly reducing the possibility of high-voltage breakdown in the accelerator's accelerating components and improving the accelerator's daily operating efficiency. The shutdown speed of the rapid shutdown system in this embodiment is no less than 1 km / s, and the complete shutdown time is no more than 9 ms.

[0076] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A rapid shut-off system for linear induction accelerators, characterized in that, This includes a rapid-closing valve assembly, a control system, and an external pulse signal system; The fast-closing valve assembly is installed in the beam drift pipe of the beam transport and focusing system of the linear induction accelerator; The rapid-closing valve assembly is in the open state when the electron beam is propagating in the beam drift channel; After the electron beam passes through the rapid-closing valve assembly, the rapid-closing valve assembly closes under the trigger signal of the external pulse signal system and the control system to block the backflow of metal particles generated in the linear induction accelerator; the rapid-closing valve assembly includes a control door, a piston, a pneumatic transmission device, a cavity wall, and a monitoring column; The cavity wall is a pipe structure with openings at both ends, and a control door is provided at one of the openings; the control door is a circular structure that can completely close the opening of the cavity wall. The top of the control door is connected to the bottom of the pneumatic transmission device, and the top of the pneumatic transmission device is connected to a piston. The control door rotates counterclockwise or clockwise under the drive of the piston and the pneumatic transmission device, thereby realizing the opening or closing of the control door. The piston is located inside the piston chamber, and an external gas pipe seat is provided on the piston chamber. The external gas pipe seat is connected to a gas supply pipe for filling the piston chamber with gas. The monitoring column is located on top of the quick-closing valve assembly and is connected to the piston for monitoring the movement of the piston and the control door. The closing speed of the rapid shutdown system is not less than 1 km / s, and the complete shutdown time is not greater than 9 ms.

2. The rapid shut-off system for a linear induction accelerator according to claim 1, characterized in that, A sealing groove is provided on the inner wall of the cavity tube near the control door at one end, which is used to achieve a vacuum seal between the control door and the cavity tube wall.

3. The rapid shut-off system for a linear induction accelerator according to claim 1, characterized in that, The openings at both ends of the cavity tube wall are respectively sealed and connected to the beam drift pipe of the linear induction accelerator. The part of the quick-closing valve assembly other than the cavity tube wall is connected to the beam drift pipe through the cavity tube wall, and the vacuum degree is kept consistent.

4. The rapid shut-off system for a linear induction accelerator according to claim 1, characterized in that, The closing diameter of the quick-closing valve assembly is 100mm.

5. A rapid shut-off system for a linear induction accelerator according to claim 1, characterized in that, When the quick-closing valve assembly is in the fully open state, the monitoring column extends 25mm beyond the top of the quick-closing valve assembly.

6. A rapid shut-off system for a linear induction accelerator according to any one of claims 1-5, characterized in that, The control system includes a control panel; The control panel has three status switches and two valve open / close indicator lights on the front. The three status switches are the local key, the lock key, and the remote key; The two valve opening / closing indicator lights are the valve open light and the valve closed light, respectively. The back of the control panel is equipped with a valve connection pipe seat and an external trigger signal connection pipe seat; The valve connection pipe seat is used to connect the control system to the fast-closing valve assembly, so as to transmit the pulse trigger signal output by the control system to the fast-closing valve assembly, thereby controlling the opening and closing actions of the fast-closing valve assembly; The external trigger signal connector is used to connect the external pulse signal system to the control system, so as to transmit the pulse signal output by the external pulse signal system to the control system.

7. A rapid shut-off system for a linear induction accelerator according to claim 6, characterized in that, The external pulse signal system includes a synchronous triggering control and monitoring system for a linear induction accelerator and a signal source; The synchronous triggering control and monitoring system is connected to the signal source; The pulse signal emitted by the synchronous trigger control and monitoring system is transmitted to the signal source; The signal source generates a pulse signal with varying amplitude and width, and loads it into the control system, which remotely controls the opening and closing actions of the rapid-closing valve assembly.

8. A method for operating a rapid shutdown system according to any one of claims 1-7, characterized in that, include: The linear induction accelerator is activated, and its injector generates a pulsed electron beam. After passing through the acceleration component system and the beam transport and focusing system, the electron beam moves toward the bremsstrahlung target at a speed close to the speed of light and a beam spot size on the order of millimeters, and interacts with the bremsstrahlung target. When the electron beam propagates within the beam drift channel, the rapid-closing valve assembly is in the open state; When the electron beam passes through the fast-closing valve assembly, the external pulse signal system generates a pulse signal and transmits it to the control system, changing the triggering method of the control system to control the valve action and triggering the closing action of the fast-closing valve assembly.

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